/**
 * (C) Copyright IBM Corp. 2010, 2015
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

package com.ibm.bi.dml.api;

import java.util.ArrayList;

import com.ibm.bi.dml.api.monitoring.Location;
import com.ibm.bi.dml.parser.Expression;
import com.ibm.bi.dml.parser.LanguageException;
import com.ibm.bi.dml.runtime.instructions.Instruction;
import com.ibm.bi.dml.runtime.instructions.spark.SPInstruction;

/**
 * The purpose of this proxy is to shield systemml internals from direct access to MLContext
 * which would try to load spark libraries and hence fail if these are not available. This
 * indirection is much more efficient than catching NoClassDefFoundErrors for every access
 * to MLContext (e.g., on each recompile).
 * 
 */
public class MLContextProxy 
{
	
	private static boolean _active = false;
	
	/**
	 * 
	 * @param flag
	 */
	public static void setActive(boolean flag) {
		_active = flag;
	}
	
	/**
	 * 
	 * @return
	 */
	public static boolean isActive() {
		return _active;
	}

	/**
	 * 
	 * @param tmp
	 */
	public static ArrayList<Instruction> performCleanupAfterRecompilation(ArrayList<Instruction> tmp) 
	{
		if(MLContext.getActiveMLContext() != null) {
			return MLContext.getActiveMLContext().performCleanupAfterRecompilation(tmp);
		}
		return tmp;
	}

	/**
	 * 
	 * @param source
	 * @param targetname
	 * @throws LanguageException 
	 */
	public static void setAppropriateVarsForRead(Expression source, String targetname) 
		throws LanguageException 
	{
		MLContext mlContext = MLContext.getActiveMLContext();
		if(mlContext != null) {
			mlContext.setAppropriateVarsForRead(source, targetname);
		}
	}
	
	public static MLContext getActiveMLContext() {
		return MLContext.getActiveMLContext();
	}
	
	public static void setInstructionForMonitoring(Instruction inst) {
		Location loc = inst.getLocation();
		MLContext mlContext = MLContext.getActiveMLContext();
		if(loc != null && mlContext != null && mlContext.getMonitoringUtil() != null) {
			mlContext.getMonitoringUtil().setInstructionLocation(loc, inst);
		}
	}
	
	public static void addRDDForInstructionForMonitoring(SPInstruction inst, Integer rddID) {
		MLContext mlContext = MLContext.getActiveMLContext();
		if(mlContext != null && mlContext.getMonitoringUtil() != null) {
			mlContext.getMonitoringUtil().addRDDForInstruction(inst, rddID);
		}
	}
	
}
